This dissertation explores the role of ideas, paradigms and ideology in the definition of public policies. To understand this issue, the thesis developed a conceptual framework and a set of propositions based on the academic literature related to the meaning of ideas and paradigm change in public policy, the impact of epistemic communities, the influence of legacies and the role of ideology from the perspective of the socio-cognitive school of Critical Discourse Analysis. In this dissertation ideology is understood as the 'fundamental beliefs of a group and its members' (Van Dijk, 2004: 6) that form the basis of social practices (Van Dijk, 2004: 9) whereas paradigms have been defined as 'taken for granted world views (...) that constrain the range of policy choices' (Campbell, 2002: 21) and in turn are bounded by ideology. The research examines the case of the Catalan National Agreement on Research and Innovation (CNARI) which was developed between 2007 and 2008. To capture and analyse this process of policy design the research uses qualitative methods that include face to face interviews, documentary research and coding of visual and textual data. The findings suggests that the design of the CNARI was based on ideas that were firmly placed within a widely acknowledged overall paradigm in innovation policy that itself was shaped and limited by a dominant broader ideology. Factors influencing the role of these ideas included the fact that the underlying paradigm was widely shared across different political territories and levels within Europe, and that the ideas were propagated by two key international organisations (EU and OECD) as well as by a number of highly respected representatives of the international epistemic community, which served to re-enforce the overarching policy paradigm, introduced these policy ideas to the Catalan context, and supported their regional adaptation. The dissertation identifies three proposals for future research: 1) an examination of the role of organisational structures in elaborating and implementing policy which does not involve civil servants, 2) an exploration of how a politician's personal experience impacts the elaboration of a political programme, and 3) an analysis of the role of open and participatory processes to define policies.